Its fatty acid profile generally consists of 70% unsaturated fatty acids (18% monounsaturated, and 52% polyunsaturated), 26% saturated fatty acids.[3] When it is fully hydrogenated, its profile is 94% saturated fat and 2% unsaturated fatty acids (1.5% monounsaturated, and 0.5% polyunsaturated).[3] According to the cottonseed oil industry, cottonseed oil does not need to be hydrogenated as much as other polyunsaturated oils to achieve similar results.[2]

Gossypol is a toxic, yellow, polyphenolic compound produced by cotton and other members of the order Malvaceae, such as okra.[4] This naturally occurring coloured compound is found in tiny glands in the seed, leaf, stem, tap root bark, and root of the cotton plant. The adaptive function of the compound facilitates natural insect resistance. The three key steps of refining, bleaching and deodorization in producing finished oil act to eliminate the gossypol level. Ferric chloride is often used to decolorize cotton seed oil.[5]

Once processed, cottonseed oil has a mild taste and appears generally clear with a light golden color, the amount of color depending on the amount of refining.[11] It has a relatively high smoke point as a frying medium. Density ranges from 0.917 g/cm3 to 0.933 g/cm3.[12] Like other long-chain fatty acid oils, cottonseed oil has a smoke point of about 450 °F (232 °C),[4] and is high in tocopherols, which also contribute its stability, giving products that contain it a long shelf life, hence manufacturers' proclivity to use it in packaged goods.

The by-product of cotton processing, cottonseed was considered virtually worthless before the late 19th century.[13] While cotton production expanded throughout the 17th, 18th, and mid 19th centuries, a largely worthless stock of cottonseed grew.[13] Although some of the seed was used for planting, fertilizer, and animal feed, the majority was left to rot or was illegally dumped into rivers.[14]

In the 1820s and 1830s Europe experienced fats and oils shortages due to rapid population expansion during the Industrial Revolution and the English blockade during the Napoleonic Wars.[14] The increased demand for fats and oils, coupled with a decreasing supply caused prices to rise sharply.[13] Consequently, many Europeans could not afford to buy the fats and oils they had used for cooking and for lighting.[13] Many United States entrepreneurs tried to take advantage of the increasing European demand for oils and America’s increasingly large supply of cottonseed by crushing the seed for oil.[14] But separating the seed hull from the seed meat proved difficult and most of these ventures failed within a few years.[14] This problem was resolved in 1857, when William Fee invented a huller, which effectively separated the tough hulls from the meats of cottonseed.[13] With this new invention, cottonseed oil began to be used for illumination purposes in lamps to supplement increasingly expensive whale oil and lard.[13] But by 1859, this use came to end as the petroleum industry emerged.[13]

Cottonseed oil then began to be used illegally to fortify animal fats and lards.[13] Initially, meat packers secretly added cottonseed oil to the pure fats, but this practice was uncovered in 1884.[13]Armour and Company, an American meatpacking and food processing company, sought to corner the lard market and realized that it had purchased more lard than the existing hog population could have produced.[13] A congressional investigation followed, and legislation was passed that required products fortified with cottonseed oil to be labeled as ‘‘lard compound.”[14] Similarly, cottonseed oil was often blended with olive oil. Once the practice was exposed, many countries put import tariffs on American olive oil and Italy banned the product completely in 1883.[14] Both of these regulatory schemes depressed cottonseed oil sales and exports, once again creating an oversupply of cottonseed oil, which decreased its value.[14]

It was cottonseeds depressed value that lead a newly formed Procter & Gamble to utilize its oil.[14] The Panic of 1837 caused the two brothers-in-law to merge their candlestick and soap manufacturing businesses in an effort to minimize costs and weather the bear market.[13] Looking for a replacement for expensive animal fats in production, the brothers finally settled on cottonseed oil.[13] Procter & Gamble cornered the cottonseed oil market to circumvent the meat packer's monopoly on the price. But as electricity emerged, the demand for candles decreased.[14] Procter and Gamble then found an edible use for cottonseed oil. Through patented technology, the brothers were able to hydrogenate cottonseed oil and develop a substance that closely resembled lard.[13] In 1911, Procter & Gamble launched an aggressive marketing campaign to publicize its new product, Crisco, a vegetable shortening that could be used in place of lard.[15] Crisco placed ads in major newspapers advertising that the product was "easier on digestion...a healthier alternative to cooking with animal fats. . . and more economical than butter.”[16] The company also gave away free cookbooks, with every recipe calling for Crisco.[16] By the 1920s the company developed cookbooks for specific ethnicities in their native tongues.[16] Additionally, Crisco starting airing radio cooking programs.[16] Similarly, in 1899 David Wesson, a food chemist, developed deodorized cottonseed oil, Wesson cooking oil.[14] Wesson Oil also was marketed heavily and became quite popular too.[14]

Over the next 30 years cottonseed oil became the pre-eminent oil in the United States.[13] Crisco and Wesson oil became direct substitutes for lard and other more expensive oils in baking, frying, sautéing, and salad dressings.[13] But by World War Two cottonseed oil shortages forced the utilization of another direct substitute, soybean oil.[13] By 1944, soybean oil production outranked cottonseed oil production due to cottonseed shortages and soybean oil costs falling below that of cottonseed oil.[13] By 1950, soybean oil replaced cottonseed oil in the use of shortenings like Crisco due to soybeans comparatively low price.[13] Prices for cottonseed were also increased by the replacement of cotton acreage by corn and soybeans, a trend fueled in large part by the boom in demand for corn syrup and ethanol.[13] Cottonseed oil and production continued to decline throughout the mid and late 20th century.[13]

In the mid to late 2000s, the consumer trend of avoiding trans fats, and mandatory labeling of trans fats in some jurisdictions, sparked an increase in the consumption of cottonseed oil,[17] with some health experts[18]:220 and public health agencies[19] recommending it as a healthy oil. Crisco and other producers have been able to reformulate cottonseed oil so it contains little to no trans fats.[20] Still, some health experts claim that cottonseed oil’s high ratio of polyunsaturated fats to monounsaturated fats and processed nature make it unhealthy.[21]

In an agricultural context, the toxicity of cottonseed oil may be considered beneficial: Oils, including vegetable oils, have been used for centuries to control insect and mite pests.[24] This oil has been generally considered the most insecticidal of vegetable oils.[24]